DNA base composition determines the specificity of UvrABC endonuclease incision of a psoralen cross-link.
The sequences flanking a psoralen interstrand cross-link may determine how it is repaired. Our comparison of the Escherichia coli UvrABC endonuclease incision of a variety of specific cross-link sequences in a single natural DNA fragment showed that DNA base composition determines which of two cross-linked DNA strands will be incised. G/C enrichment of the region 6-12 bases 5' of the modified T on the furan-side strand results in preferential incision of the furan-side strand. When the G/C-rich region is on the 3' side, or on neither side, incisions occur on either strand. These effects of DNA base composition suggest that UvrAB can bind in two ways to a psoralen cross-link.
Jones
B K
BK
Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111.
Yeung
A T
AT
D001482:Base Composition; D001483:Base Sequence; D003432:Cross-Linking Reagents; D004247:DNA; D004260:DNA Repair; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D029968:Escherichia coli Proteins; D011564:Furocoumarins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D015183:Restriction Mapping; D013379:Substrate Specificity
D003432:Cross-Linking Reagents; D029968:Escherichia coli Proteins; D011564:Furocoumarins; D004247:DNA; D004706:Endodeoxyribonucleases; C036385:endodeoxyribonuclease uvrABC